It must really piss off Republicans, but Bill Clinton is hugely popular, so using him to campaign for Obama is just good politics.
CLINTON: This election, to me, is about which candidate is more likely to return us to full employment. This is a clear choice. The Republican plan is to cut more taxes on upper income people and go back to deregulation, that's what got us in trouble in the first place. President Obama has a plan to rebuild America from the ground up, investing in innovation, education, and job training. It only works if there is a strong middle class. That's what happened when I was president. We need to keep going with his plan.
It's especially smart to use him in this spot, which is targeting middle class voters. Right now, they prefer the Democratic ticket 52-42 over the Romney-Ryan, and the Democrats clearly think they can build on that margin now that Paul Ryan and his zeal for slashing middle and working class programs is on the ticket. And very few politicians can articulate the issues as clearly and compellingly as Clinton.
One unfortunate thing to note about the ad is that it was President Clinton who signed the Gramm-Leach-Billey Act which repealed Glass-Steagall, as well as the Commodity Futures Modernization Act, which deregulated the derivatives market. Clinton, to his credit, later admitted that was a mistake.
But he's absolutely right -- the entire Republican economic plan consists of repealing Dodd-Frank, Obamacare, and pretty much anything else the US Chamber of Commerce wants, plus cutting taxes for rich people. We've seen that movie before. And by just appearing in the ad, Clinton will remind everyone who doesn't have an offshore bank account that their lives got better in the 1990s, and got much worse in the Bush '00s.